Prince George and Charlotte played key roles at the weddings of Prince Harry and Princess Eugenie, leading the bridal parties at both events.

The Duke and Duchess of Sussex are also set to be missing from Lady Gabriella's wedding, as will Prince Charles and his wife Camilla, the Duchess of Cornwall.

Even the Queen and Prince Philip are expected to be snubbed from the occasion.

That's despite Lady Gabriella being the daughter of one of the Queen's cousins. Lady Gabriella's father is Prince Michael, who is the Queen's first cousin.

Princess Charlotte and Prince George at the wedding of Princess Eugenie at Windsor Castle. (Getty)

Gabriella's grandfather was Prince George of Kent, the younger brother of the Queen's father, King George VI.

Lady Gabriella's wedding is expected to be an intimate ceremony, with just close family and friends to attend.

Royal expert Richard Fitzwilliams told Express: "Senior members of the royal family were absent from the marriage of [Lady Gabriella's] brother Lord Frederick Windsor to the actress Sophie Winkelman in 2009.

"It’s a relatively low profile occasion as royal weddings go but given the insatiable appetite for royal news, there was more buzz around Eugenie’s wedding than expected, there will undoubtedly be interest in it."

Lady Gabriella's father, Prince Michael, is occasionally seen at royal gatherings with his family and sometimes carries out engagements on behalf of the Queen.

But it’s Lady Gabriella's mother, Princess Michael of Kent, who has made headlines recently for all the wrong reasons.